- 期刊
水溶性奈米硫化鎘量子點之製備及其螢光特性
Preparation and fluorescence properties of water soluble cadmium sulfide quantum dot
摘要
本研究採用玻尿酸（Hyaluronic acid，簡稱HA）作為表面修飾劑（Surface modifier），開發安全且快速之硫化鎘（CdS）量子點（Quantum Dot，簡稱QD）水溶性製備法。鎘離子溶液在特定pH值，添加有助微粒分散之表面修飾劑；以每分鐘0.2ml硫離子溶液相同莫耳濃度，持續攪拌加入溶液中，再輔以超音波震盪持續30分鐘，使晶格穩定可得QD產物。研究探討鎘鹽及含硫試劑種類、表面修飾劑濃度、pH值等製備參數，對QD之影響。在三種鎘鹽種類與兩種硫試劑合成QD之結果比較下，發現以氯化鎘製備之QD具有最大螢光亮度，推論對應離子與QD表面鎘之配位，將影響螢光亮度。本研究亦嘗試改變HA濃度（0%~0.02%），添加0.01%有最大螢光亮度，而0.02%以上螢光亮度不增反遞減，推測可能因表面修飾劑過量而遮閉螢光。改變pH值(1~11)，結果發現pH5螢光亮度最大與表面修飾劑特性有關。在第24小時，達平衡並具有最大螢光強度；螢光產率可高達60％，持續觀察30天後仍具有在原始之90%螢光亮度。以FIA對CdS QD定量分析，在0.1mM ~2.0mM範圍內，具良好線性關係R2=0.9973、良好再現性RSD＜0.1（n=5）。本研究製備之CdS QD具有優異之螢光特性，而不同化合物錯合而改變螢光強度之現象。未來將來可運用在化妝品活性成分之分析。
並列摘要
We use Hyaluronic acid（HA）as a surface modifier（Surface modifier）to develop the preparation of water-soluble cadmium sulfide (CdS) quantum dot （QD）,which is safe and quick. Under certain pH value, the addition of surface modifier helps to disperse the microparticle of Cd^(2+). the S^2- are added at a rate of 0.2 ml/minute to the solution, stirring and sonicating for 30mins, and get a stable QD product. In our study, we investigate the effect of parameter on the formation of QD, including three kinds of Cd salts, two kinds of sulfur–containing reagents, the concentration of surface modifier and pH value. Comparison the synthesis of QD with different kinds of Cd salts and different kinds of sulfur-contaning reagents, we found that the preparation of QD with CdCl^2 and Na^2S yielded the strongest fluorescence intensity. We also tried to investigate the concentration of HA(0%~0.02%) on QD fluorescence intensity, and found out that the addition of 0.01% HA yielded the strongest fluorescence intensity. If HA with concentration more than 0.02% ,on the contrary, yielded all the weaker fluorescence intensity was observed. It is postulated that the excess of surface modifier may have the potential to shield fluorescence. Besides the pH value of 5 yielded the strongest fluorescence intensity and the result showed that the fluorescence intensity is relevant to the properties of surface modifier. Based on the optimum conditions, our CdS QD had the properties as follows, λ_(Ex) : 350nm, λ_(Em): 698nm, the reaction was completed at 24th hour and yielded the stable fluorescence intensity, the fluorescence yield reached 60%, 90% of fluorescence intensity remained after 30 day. On the other hand, the quantity analysis of CdS QD with FIA at a range of 0.01mM~2.0mM revealed good linear relation (R^2 = 0.9973) and good reproducibility (RSD＜0.1,n=5). We prepared had a superior fluorescence properties, which can be applied to the analysis of cosmetics actwe ingredients.